The aim of this 4-study, laboratory-based project is to investigate how dispositional (sexual prejudice, gender role beliefs, masculine gender role stress, psychopathy), situational (alcohol intoxication, gender role violations), affective, and contextual variables (provocation, masculinity threats) facilitate antigay aggression. In Studies 1-3, aggression will be measured using a modified version of the Taylor Aggression Paradigm (Taylor, 1967) in which participants administer and receive mild electric shocks to/from a fictitious opponent under the guise of a competitive reaction time task. Dispositional variables will be measured using validiatd self-report measures. Each study will recruit 320 adult male heterosexual participants who will be randomly assigned to compete against a heterosexual or gay male. However, each study will examine the effects of different experimental manipulations (that correspond to the long-term goals of the project) on antigay aggression. Study 1 participants will view a video depicting gender conforming or non-conforming behavior between heterosexual or gay male dyads, respectively; Study 2 participants will experience a masculinity threat from a male confederate; Study 3 will examine the effect of acute alcohol intoxication on antigay aggression toward heterosexual and homosexual men and women. Each study will assess state affect via self-report scales before and after presentation of the stimulus videos. In Studies 2 and 3, state masculine affiliation will be assessed after participants receive feedback from a male peer and after completing the competitive reaction time task. Study 4 will explore the interactive effect of sexual prejudice, gender role violations, and dispositional variables on state affect in women. Participants will be 120 adult heterosexual women who complete dispositional inventories and measures of state affect and view a video depicting either gender conforming or non-conforming behavior between heterosexual or lesbian dyads, respectively. This project will identify risk factors for antigay violence in men as well as provide new data regarding female sexual prejudice. In doing so, we will improve our knowledge of antigay violence and discrimination which, in the future, may facilitate the development of prevention and treatment interventions.